The present invention relates to a restraint system having a restraint device for protecting at least one passenger, and to a method for controlling a restraint system.
From the German Published Patent Application No. 197 13 087, a vehicle passenger restraint system is known which has an acceleration sensor for measuring the acceleration of the motor vehicle, an analog/digital converter for digitalizing the output signals of the acceleration sensor, a wavelet transformer for transforming the digital signals in order to generate wavelet coefficients, and a device for calculating the speed, an actuator for the restraint system being activated as soon as the change in speed and the wavelet coefficient each exceed preestablished threshold values.
The wavelet coefficient is calculated using a wavelet function which was generated from a master wavelet function using a scaling factor and a displacement parameter for the time shift.
In contrast, the restraint system according to the present invention having a restraint device for protecting at least one passenger, and the method according to the present invention for controlling a restraint system, have the advantage that as a result of distinguishing between crash types and by evaluating the braking acceleration energy, an optimal triggering time point is determined for the restraint system. As a result, the triggering of the restraint system is more situation-appropriate.
It is particularly advantageous that the crash types are determined on the basis of extracted features, using a comparison of records of learned and stored features. In this way, an unambiguous identification of the specific crash type is possible, so as to decide whether the restraint system should be triggered or not. Not every crash calls for the triggering of the restraint system. Among such are, for example, front-end crashes having a velocity of maximum 15 km/h or a rear-end crash. In addition, spurious signals are identified in this way and therefore advantageously do not lead to a triggering of the restraint device.
In addition, it is advantageous that between the learned features and the extracted features differences are calculated, and these differences are compared to a preestablished threshold value, so that an identification of a crash type only takes place when a threshold value is not exceeded. In other words, only then is the difference so small that one can speak of an identification of this feature.
It is also advantageous that the measure for the braking acceleration energy is also compared to a second threshold value, so that the triggering actually takes place only if the crash type requires a triggering and if the measure lies above the threshold value, so that a triggering is therefore necessary. Both conditions must therefore be fulfilled in order to generate a triggering. In this way, advantageously, spurious triggerings become less likely, and therefore triggering a restraint device becomes more reliable.